Disease and Pest of Cole Crops
INSECT PESTS OF COLE CROPS
1. Mustard saw-fly
Scientific name: Althalia proxima klug.
The blackish caterpillar that attacks all cole crops and feeds on the leaves of young seedlings in the early stages. The infested leaves curled and fell on the ground when touched.
Control measures
(i) Hand-picking of caterpillar, if the infestation is light and the number of the attacked plant is small, is the best method of controlling the larvae.
(ii) Spray the crop with malathion 50 EC @ 1000 ml/ha quinolphos 25 EC @ 625ml/ha. All this should be applied in about 600 to 700 liters of water per ha.
2. Mustard aphids
Scientific name: Lipaphis erysimi Davis.
A greenish-white small insect that attaches to cabbage and other cole crops when there is cloudy weather. They suck the sap from the plants. The affected leaves get curled, and plants wither and die.
Control measures
1) Use tolerant varieties 2) Set up a yellow stick trap to monitor the aphid population. 3) Destroy the affected parts along with the aphid population in the initial stage 4)Spray the crop with one of the following in the flowering stage; oxydemeton methyl, dimethoate at 625–1000 ml per ha.
3. Diamond Black Moth
Scientific name : Plutella maculipennis Curt.
A small slender pale green caterpillar that feeds on leaves and makes holes in them. The infested crops become unsuitable for marketing.
Control measures
This pest can effectively be controlled by spraying the crops with Malathion (Cythion-50 EC, Sumithion-50 EC, Folithion-1000) @ 2 ml per liter of water, Diochlorovos (Nuvan-1000, Vapona, Agrodan, etc.), or Monocrotophos (Monocil, Nuvacron, Suphos, etc.) @ 1 ml per liter of water.
4. Cabbage borer
Scientific name: Hellula undalis F.
A whitish brown caterpillar that mines the leaves and feeds on shoots. Later, it burrows into the stem of cabbage. The affected plants wilt, remain dwarf, or may even die.
Control measures
(i) Removal of caterpillars when the plant is young is the best method for the control of larvae. (ii) This pest can effectively be controlled by spraying the crop with Phosphamidon (Demicron-100 EC, Sumidon, Demidon, etc.) @ 0.5 ml per liter of water or Methyl parathion (Metacid-50 EC, Methyl Parathion 50 EC, Chlorophs 50 EC @ 1 ml per liter of water.
5. Cabbage fly
Scientific name: Chrotophila (Hylemya) brassicae.
The maggots first attack the young rootlets and then burrow into the main root. The affected plants become yellow, and sometimes they may die.
Control measures
Soil application of Aldrin or Heplachlor 5 percent @ 15 kg per acre or Heptaf 5 percent @ 10 kg per acre at the time of planting has been found effective in controlling this pest.
6. Painted bug
Scientific name : Bagada cruciferarum kirk.
The adult and nymph of this post suck the sap from the plants and retard their normal growth.
Control measures
1) Use tolerant varieties. 2) Set up a yellow sticky trap to monitor the aphid population. 3) Destroy the affected parts along with the aphid population in the initial stage 4) Spray the crop with one of the following in the flowering stage: oxydemeton methyl, dimethoate at 625–1000 ml per ha.
DISEASES OF COLE CROPS
1. Leaf spot and blight
C.O.: Alternaria brasicicola and A. brassicae.
Small dark-colored spots that spread rapidly to form circular lesions and concentric rings of dark conidiophores appear in humid weather, due to which cauliflower develops brown discoloration, and cabbage, after harvest, acquires a black, mouldy appearance.
Control measures
(1) Hot water treatment of seeds at 50°C for 30 minutes helps to check the spread of this disease.
(ii) Spraying the crop with Zineb (Dithane Z-78) or Mancozeb (Dithane M-45) @ 2.5 gm per liter of water or Copper oxychloride (Blitox, Blucopp Phytolan, Cupravit, etc.) @ 5 gm per liter of water at an interval of 10-15 03 according to the incidence of the disease is very effective to control this disease
2. Black rot
C.O.: Xanthomonus (Pseudomonas) capestris.
The margin of disease-affected leaves turns yellow, veins become visible, and vascular discoloration takes place in the main stem. Tavo becomes dark, and the main stem of the cauliflower heads is discolored. The seedling may die when attacked at a young stage.
Control measures
The disease can be controlled by seed treatment with hot water at 50°C or one percent mercuric chloride solution for half an hour before sowing and adopting crop rotation with non-cruciferous crops for three years.
3. Club rot
C.O.: Plasmodiophora brassicae
The roots of affected plants enlarge to form ‘clubs’; secondary invasion by soft root bacteria follows, forming materials toxic to plants. The foliage of affected plants wilts on sunny days and recovers toward evening.
Control measures
The seedlings at transplanting time should be treated with mercuric chloride at 125 c.c. (about 113.4 gm) per 100 seedlings.
4. Damping off
C.O. : Phythium aphandidermatumCorticum solani Sclerotium rolfsi
It is a common problem in the nursery bed of vegetable crops. The affected plants fall down and die due to the shrinking of cortical tissue of hypocotyl.
Control measures
Drenching the nursery bed with formaldehyde or Brassicol about 3-4 weeks before sowing, seed treatment with mercurial fungicide @ 2 gm per kg of seed, avoiding thick sowing, and spraying the seedlings with Dithane M-45 or Dithane Z-78 @ 2.5 gm per liter of water are the common remedial measures.
Read further:
Insecticide Formulations and their Calculation: A brief Information
Composition Profile Properties and Classification of Soil in India
